Transcript Additives FaFL JDT amendedA2

Food additives
© Food – a fact of life 2009
Foundation
What are food additives?
Food additives are substances added to products to
perform specific technological functions. These
functions include preserving, i.e. increasing shelf-life or
inhibiting the growth of pathogens, or adding
colouring and flavouring to food for interest and
variety.
There are over 300 permitted additives that can be
used in the UK. Flavourings are not included in this
figure, as there are over 3,000 flavouring components
in UK use, in many different combinations.
International organisations provide advice on the
safety of flavourings.
© Food – a fact of life 2009
Why additives are used
• Food safety e.g. use of preservatives, to prevent food poisoning, decay
and spoilage
• To make the food last longer or prolong shelf life, e.g. use of anti-oxidants,
to prevent enzymic oxidation and rancidity occurring or emulsifiers,
stabilisers and humectants, to ensure food products remain palatable
• Sensory appeal e.g. in the use of colourings, flavourings, to attract the
consumer to the product or improve or enhance the flavour, colour and
texture of food
• To produce a uniform food during large scale manufacture (all exactly the
same)
• To provide easy-to-prepare convenience foods in a society that is busy
and spends less time in the kitchen
• To produce new food products e.g. snacks and confectionary in novelty
shapes and colours
• To restore original characteristics of a product
• To restore or increase nutritional value
• Large scale manufacturing e.g. use of anti-foaming and anti-caking
agents, to ensure the successful production of products in the commercial
setting
© Food – a fact of life 2009
Natural or synthetic
Additives may be:
• natural – found naturally, such as extracts from
beetroot juice (E162), used as a colouring agent;
• manmade versions – synthetic identical copies of
substances found naturally, such as benzoic acid
(E210), used as a preservative;
• artificial – produced synthetically and not found
naturally, such as nisin (E234), used as a preservative in
some dairy products and in semolina and tapioca
puddings.
© Food – a fact of life 2009
Why not keep to natural additives?
Some artificial colours have almost disappeared from
foods as companies realised that many consumers
prefer food products to contain natural colours.
At present there is not the variety of natural additives
required to perform all the functions of additives
necessary.
Manmade additives may prove more efficient at
preserving, and some natural colours fade in some
products.
© Food – a fact of life 2009
Types of additives
• Preservatives
• Colours
• Sweeteners
• Flavours and flavour enhancers
• Emulsifiers and stabilisers
• Antioxidants
• Fortification
© Food – a fact of life 2009
Preservatives
Preservatives aim to
• prevent the growth of micro-organisms which could
cause food spoilage and lead to food poisoning;
• extend the shelf-life of products, so that they can be
distributed and sold to the consumer with a longer
shelf-life.
The main two on the permitted list are sulphur dioxide
and benzoic acid. For example, bacon, ham, corned
beef and other ‘cured’ meats are often treated with
nitrite and nitrate (E249 to E252) during the curing
process.
© Food – a fact of life 2009
Antioxidants
Antioxidants aim to:
• Prevent food containing fat or oil from going rancid (developing
an unpleasant odour or flavour )due to oxidation by either
absorbing oxygen or preventing chemical changes involved in
rancidity.
Hydrolytic rancidity cannot be prevented by antioxidants.
Chemical reactions involved in rancidity are prevented by using
butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT).
• Prevent the browning of cut fruit, vegetables and fruit juices and
so increase shelf life and appearance
Vitamin C (ascorbic acid) is an antioxidant that absorbs oxygen, as
does vitamin E (tocopherols). For example, vitamin C, also known
as E300, is one of the most widely used antioxidants.
* Do not mention or get confused with health related anti-oxidants (preventing cancer
etc.): this is not why manufacturers use them.
© Food – a fact of life 2009
Colours
Colours aim to:
• restore colour lost during processing or storage, e.g. marrowfat peas;
• ensure that each batch produced is identical
in appearance or does not appear ‘off’;
• reinforces colour already in foods, e.g. enhance
the yellowness of a custard;
• give colour to foods which otherwise would be colourless (e.g. soft drinks)
and so make them more attractive.
Certain combinations of the following articifical food colours: sunset yellow
(E110), quinoline yellow (E104), carmoisine (E122), allura red (E129),
tartrazine (E102) and ponceau 4R (E124) have been linked to a negative
effect on children’s behaviour.
These colours are used in soft drinks, sweets and ice cream.
The Food Standards Agency suggest if signs of hyperactivity or Attention
Deficit Hyperactivity Disorder are seen in a child, these additives should be
avoided.
© Food – a fact of life 2009
Flavour enhancers
Flavour enhancers bring out the flavour in foods
without imparting a flavour of their own, e.g.
monosodium glutamate (E612) is added to processed
foods. For example some soups, sauces and sausages.
Flavourings, on the other hand, are added to a wide
range of foods, usually in small amounts to give a
particular taste. These do not have E numbers because
they are controlled by different food laws. Ingredients
lists will say if flavourings have been used, but individual
flavourings might not be named.
© Food – a fact of life 2009
Sweeteners
Sweeteners include:
• intense sweeteners, e.g. saccharin, have a
sweetness many times that of sugar and therefore are
used in small amounts, e.g. in diet foods, soft drinks,
sweetening tablets;
• bulk sweeteners, e.g. sorbitol, have a similar
sweetness to sugar and are used at similar levels.
If concentrated cordial drinks that contain sweeteners
are given to children between the ages of 6 months
to 4 years, it is important to dilute them more than for
adults. Infants under 6 months should not be given
cordial drinks.
© Food – a fact of life 2009
Reasons for adding sweeteners
• Used to add sweetness without adding calories – good in preventing
obesity and type 2 diabetes.
• Improves the nutritional profile.
• Consumers are health conscious.
• Better for dental health and dental caries than sugar, this promotes plaque.
• Sweeteners are often chemicals, which could have, as yet, undiscovered
health effects.
• Some sweeteners have laxative effects.
• Consumers can become accustomed to sweetness, and thus expect many
foods to have a high level of sweetness which may be unnecessary.
• Consumers may be purchasing products on the basis that they contain
sweeteners, in the hope that they are low in calories, but this may not be the
case.
• The sweetness of a product may be hiding the fact that low quality
ingredients are being used.
• The use of sweeteners may increase or reduce the unit cost of a product.
• Concerns about some artificial sweeteners, like Saccharin, being
carcinogenic.
© Food – a fact of life 2009
Emulsifiers and stabilisers
Emulsifiers: These are substances, which allow water and oil to mix
(immiscible liquids). They enable the production of a stable dispersion
of oil in water or vice versa. These are used to ensure that food products
remain in a good stable condition for a certain period of time after they are
manufactured.
• Emulsifiers are used in products such as salad dressings, low-fat spreads and ice
cream. Emulsifying salts are used to change the proteins in processed cheese
into a smooth mixture with fat and water
• Example – Lecithin, glycerol monostearate (GMS), egg yolk and whey protein
• Emulsifiers work in the following ways:
• An oil and water emulsion separates after a time. Emulsifier molecules have a
water-loving (hydrophilic) head and a water-hating (hydrophobic) tail
• The water loving head is attracted to the water and the water hating tail to the
oil droplets
• So the emulsifier molecules surround the oil droplets and prevent them from
separating out
Stabilisers: These are substances that have the ability to absorb considerable
quantities of water. This property makes them good thickening agents, many being
able to produce gels. Most can act as emulsifiers and prevent fat separation.
Examples - gums, cellulose derivatives and gelatine
© Food – a fact of life 2009
Fortification (nutritional supplementation)
• Fortification involves the addition of nutrients to foods irrespective of
whether or not the nutrients were originally present in the food.
• This group include the vitamins and minerals and protein supplements. They
are only considered additives when they fulfil a technological purpose, e.g.
ascorbic acid used as an antioxidant.
• Safety and technical considerations are taken into account when deciding
which foods to fortify and to what level.
• Some nutrients must be added to foods by law, e.g. Vitamins A and D must
be added to margarine, others voluntarily (e.g. breakfast cereals).
• The purpose is to improve the nutritive value of mass produced foods to
improve the health of the nation (or potentially a sub-population). Fortified
foods make an important contribution to diets in the UK.
• Some micro-nutrients are lost in food processing and thus may be replaced
as a form of supplementation.
• Nutrients may be added to certain foods, such as iron in pasta; folic acid in
breakfast cereals; calcium in bread, to aid certain dietary groups such as
children, the elderly, vegetarians and pregnant women
© Food – a fact of life 2009
Examples of fortification
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Margarines and reduced fat spreads (because of mandatory and voluntary
fortification respectively) are important sources of vitamins A and D in the UK
diet.
Cereal and cereal products play an important role in the diet and are a major
source of many nutrients for both children and adults, due in part to the
mandatory fortification of all wheat flour (apart from whole meal) with iron,
thiamin and niacin, and all flours (except whole meal and some self-raising
varieties) with calcium.
Foods that are produced for vegans and vegetarians, such as soya products,
are often fortified voluntarily with vitamin B12. As foods from plant sources do
not naturally contain this vitamin, fortified foods are the only dietary source of
vitamin B12 for vegans. Some soya drink products are also fortified with
calcium, which is important for those who do not consume dairy products, the
major source of calcium in the UK diet.
Many manufactured foods for infants are fortified, particularly with iron and
some with vitamin D, although the nutritional composition of these products is
strictly controlled by a number of European regulations.
Other foods, such as meal replacements, sports drinks, slimming products,
and foods aimed at particular groups, are often fortified, with some
categories being controlled by specific legislation that states the amount and
types of nutrients that can be added.
© Food – a fact of life 2009
Anti-foaming agents
• These are added to liquids which have to be poured or pumped in
a factory, such as milk or fruit juices. The anti-foaming agent does
what it says; it prevents the build-up of air bubbles or foam as the
liquids are poured. If they were not used, pipes would clog up,
become blocked and leakages and wastage would occur.
Foaming agents
Used to ensure that bubbles are evenly distributed – e.g. ice cream
Anti-caking agents
• These absorb moisture from dried foods without themselves
becoming wet. They are used in dry products to ensure the
substances flow or move freely, for example, table salt and dried
milk, thus maintaining the desired texture. Examples of anti-caking
agents include: silicates, calcium phosphates, magnesium oxide,
salts from some long chain fatty acids such as stearic and palmitic.
© Food – a fact of life 2009
Others
Gelling agents are used to change the consistency of a food and
enhance texture, e.g. soya milk, pectin (E440) which is used to
make jam.
Thickeners help give food body, e.g. can be found in most sauces.
Glazing agents provide a protective coating or sheen on the
surface of foods, e.g. confectionary (for appearance and shelflife).
Humectants stop foods drying out, e.g..; soft centres of chocolates
Sequesterants stop reactions such as off flavours in fruits and
discolouration of foods
Modified starch is added to dry foods such as soups and baby
foods to add bulk and enable liquid to be incorporated
Propellants are gases that are used to make aerosols work – e.g.;
for decorating cream
Thickeners give food body and improve the texture and mouth feel
e.g.; yogurts, sauces
Acids, bases and buffers control the acidity or alkalinity of food, for
safety and stability of flavour.
© Food – a fact of life 2009